On Friday, Israel’s Channel 2 reported that rockets containing chemical agents were fired by the 155th Brigade of the 4th Armored Division, a division under the command of the Syrian president’s brother, Maher Assad.

The shells were reportedly fired from a military base in a mountain range west of Damascus, the news channel said, without disclosing its sources.

Aaron Sagui, a spokesman for the Israeli Embassy in Washington, declined to comment on the reports. But Israeli officials have said publicly that they believe last week’s attack was a chemical attack by forces loyal to President Bashar Assad.

The Syrian opposition says hundreds of people were killed in the Aug. 21 early morning shelling of rebel-controlled residential areas in the suburbs of Damascus and blames the government for the attack. Syrian officials deny any responsibility and have pointed the finger at elements of the opposition.

U.S. intelligence agencies long have relied on Israel to help provide intelligence about Syria. Israel’s spy services have many more Arabic-speakers than do the CIA and National Security Agency, and Israel is believed to have a network of spies within Syria.

Still, a former CIA officer with long Middle East experience advised skepticism of purported leaked intercepts. Israel would be reluctant to disclose that it could listen in on senior Syrian figures, he said.

“Because once you do that, it goes away,” he said, asking not to be quoted by name speaking about sensitive intelligence matters.

However, he acknowledged that Israel has superior intelligence coverage of Syria.

“They only do a few things, and they do them very well,” he said. “They collect mainly on the countries that border them, and because they focus only on those targets, they are very effective. Their technical ability is on par with much larger nations.”